coondoggie writes: "NASA said today new data show carbon dioxide-based snow, or what's more commonly known as dry ice, falls on the Red Planet's south pole -the only known such weather in our solar system.Frozen carbon dioxide requires temperatures of about minus 193 degrees Fahrenheit (minus 125 Celsius) and the new analysis is based on data from observations in the south polar region during southern Mars winter in 2006-2007, identifying a tall carbon dioxide cloud about 300 miles (500 kilometers) in diameter persisting over the pole and smaller, shorter-lived, lower-altitude carbon dioxide ice clouds at latitudes from 70 to 80 degrees south."